I'm having a problem with my 89 190E, 2.6. It is getting progressively harder to start when the engine is hot. It seems as if it is not getting enough fuel. Also after running at highway speeds, it stalls when I come to a stop in traffic. This is an intermittent problem that my wife seems to have more than me. I checked the vacuum and it is holding at the bottom of the green arc at idle, (about 15 in hg). Is this a vacuum problem or should I be looking elsewhere? When the engine is cold, (overnight) It mostly starts fine, with occasional fits of being cantankerous.